Interrelations of lead levels in bone, venous blood, and umbilical cord blood with exogenous lead exposure through maternal plasma lead in peripartum women.

Recent research has raised the possibility that fetal lead exposure is not estimated adequately by measuring lead content in maternal whole blood lead because of the variable partitioning of lead in whole blood between plasma and red blood cells. Lead in maternal plasma may derive in large part from maternal bone lead stores. In this study we aimed to estimate the contribution of maternal whole blood lead, maternal bone lead levels, and environmental lead to umbilical cord blood lead levels (as a measure of fetal lead exposure). In the model, we assumed that lead from all of these sources reaches the fetus through the maternal plasma lead pathway. In 1994-1995, we recruited 615 pregnant women for a study of lead exposure and reproductive outcomes in Mexico City. We gathered maternal and umbilical cord blood samples within 12 hr of each infant's delivery and measured maternal lead levels in cortical bone and trabecular bone by a K-X-ray fluorescence (K-XRF) instrument within 1 month after delivery. We administered a questionnaire to assess use of lead-glazed ceramics (LGC) to cook food and we obtained data on regional air lead levels during the 2 months before delivery. We used structural equation models (SEMs) to estimate plasma lead as the unmeasured (latent) variable and to quantify the interrelations of plasma lead, the other lead biomarkers, and environmental lead exposure. In the SEM analysis, a model that allowed plasma lead to vary freely from whole blood lead explained the variance of cord blood lead (as reflected by a total model R(2); R(2) = 0.79) better than did a model without plasma lead (r(2) = 0.67). Cortical bone lead, trabecular bone lead, use of LGC, and mean air lead level contributed significantly to plasma lead. The exchange of lead between plasma and red blood cells was mostly in the direction of plasma to cells. According to the final model, an increase in trabecular bone lead and cortical bone lead was associated with increases in cord blood lead of 0.65 and 0.25 microg/dL, respectively. An increase of 0.1 microg/m(3) in air lead was associated with an increase in the mean level of fetal cord blood lead by 0.67 microg/dL. With one additional day of LCG use per week in the peripartum period, the mean fetal blood lead level increased by 0.27 microg/dL. Our analyses suggested that maternal plasma lead varies independently from maternal whole blood lead and that the greatest influences on maternal plasma lead are maternal bone lead stores, air lead exposures, and recent cooking with LGC. The contributions from endogenous (bone) and exogenous (environmental) sources were relatively equal. Measurement of plasma and bone lead may be important in accurately assessing fetal lead exposure and its major sources, particularly if exogenous exposures decline.

Cardiac rehabilitation in a young patient with severe left ventricular dysfunction and stroke: a case study.

This is a case report of a 36 years old Puerto Rican female with dual disabilities: severe left ventricular dysfunction secondary to an extensive myocardial infarction and two stroke episodes, complicated with congestive heart failure, who underwent a comprehensive cardiac rehabilitation program which resulted in improvement. Strategies included a long term exercise program, with low increments, slow progression and close supervision; educational, nutritional and medical interventions, in addition to an orthotic device. This report discusses the health-related fitness and overall benefits that the patient obtained from this multifactorial program.

Air pollution and school absenteeism among children in Mexico City.

To determine the acute effects of ozone exposure, the authors conducted a short follow-up study of respiratory illness in a population of 111 preschool children frequently exposed to ozone levels that regularly exceed 0.120 parts per million (ppm). The children attended a private kindergarten in the southwestern part of Mexico City. Parents completed a questionnaire on demographic data, medical history, and potential sources of indoor air pollution. To determine the relation of ozone and respiratory-related school absenteeism, the authors used a logistic regression model for longitudinal data. During the 3-month follow-up, 50% of the children had at least one respiratory-related absenteeism period, and 11.7% had two or more. Children exposed for 2 consecutive days to high ozone levels (> or = 0.13 ppm) had a 20% increment in the risk of respiratory illness. For children exposed for 2 consecutive days to a high ozone level and the previous day to low temperature (< or = 5.1 degrees C), the risk reached 40% (odds ratio = 1.44, 95% confidence interval 1.37-1.52). This study suggests that ozone exposure might be positively associated with the risk of respiratory illness in children and that it may have an interactive effect with low temperature exposure.